Variable speed mechanism



June 1 7, 1947. (5.. F. LAliNIG 2,422,306

VARIABLE S FEED MECHANI SM Filed July 28, 1944 2 SheetsSheet 2 INVENTOR. Gmwozv Fl LAING ATTYI Patented June 17, 1947 VARIABLE SPEED MECHANISM Gordon F. Laing, Delavan, Wis., assignor to The George W. Borg Corporation, Chicago, 111., a

corporation of Delaware Application July 28, 1944, Serial No. 547,041

9 Claims.

The present invention relates in general to variable speed mechanisms; and the object of the invention is to produce a new and improved mechanism of this character.

More in particular, the object of the invention is the production of a simple and efiicient variable speed mechanism by means of which an output speed varying by extremely small increments over a wide range may be derived from a given input speed, the arrangement being such, moreover, that any desired output speed within the range of the mechanism may be accurately predetermined and reproduced at will.

The invention may have various applications, but is especially useful as a variable speed wire pulling mechanism for the production of tapered conductors as disclosed in the pending application of Thomas B. Gibbs et al., Ser. No. 525,764, filed March 9, 1944.

The invention will be described more in detail hereinafter, reference being had to the accompanying drawings, in which Fig. 1 is a front view of a variable speed mechanism embodying the invention;

Fig. 2 is a top view of the same, with the cover removed;

Fig. 3 is a detail showing the construction of the adjustable yoke for supporting the idler balls; and

Fig. i is a plan view of one of the ball races used in the bearings for the idler balls.

Referring to the drawings, the reference character It! indicates a suitable casing, the shape of which will be readily understood from Figs. 1 and 2. The casing may be an iron casting, or it may be fabricated from steel plates secured together by machine screws, or in any suitable manner, as by welding. A cover II is provided, shown only in Fig. l, and is removably secured to the casing by machine screws as shown.

The input shaft is indicated at l2 and may be driven in any suitable manner. It may be, for example, the shaft of a small motor mounted on the cover H, and in this case no additional bearings will usually be required. A bearing may be provided at the cover ll, however, if desired, and also at the bottom of the casing.

The shaft l2 carries a worm l3, which is in mesh with the worm gear l4. Gear M is carried on the transverse shaft l5, which has suitable bearings in the sides of the casing H) as shown.

The output shaft is indicated at I6 and is an extension of the transverse shaft I! which is similar to shaft l and is provided with similar bear ings in the sides of the casing.

The intermediate shaft I8 is similar to shafts l5 and ii. The bearings are the same also, except that whereas the thrust bearings 32 and 34 for shafts I5 and I! are in the same wall of the casing the thrust bearing 33 for shaft I8 is in the opposite wall.

The shaft l! is driven from shaft l5 by means of the three discs l9, 2|] and 2|, mounted on shafts l1, l8 and I5, respectively, and two sets of idler balls for coupling the discs together. The first set comprises idler balls 22 and 23, which transmit motion from disc 2! 'to disc 20. The'second set, for transmitting motion from disc 20 to disc l9, comprises the idler balls 24 and 25. The discs and balls are preferably made of hardened steel.

The three shafts l1, l8 and [5 are in horizontal alignment. The idler balls of each set are'aligned on a thrust axis which is parallel to and in the same horizontal plane as the shafts.

The two sets of idler balls are supported by means of ball bearings on a yoke 26. The bearing for the ball 22 of the first set includes the two ball races 2'! and 28, indicated in Fig. 2 and shown clearly in Fig. 3. The ball race'2'l is also shown in Fig. 4. The races 21 and 28 are fitted at the opposite sides of a rectangular opening in the yoke 26 and are restrained against movement in two directions but are free to slide in a third direction, i. e., in a direction parallel to the thrust axis of the balls 22 and 23. It will thus beseen that the races 21 and 23 and their associated balls support the ball 22 for rotation about an axis which is perpendicular to the thrust axis of the balls 22 and 23 and that the rotational axis is movable in the direction of the thrust axis to accommodate any slight movement of the ball '22 along this axis that may be required. Ball 23 is supported by the ball races 29 and 3!] and their associated balls in the same way as described in the case of ball 22.

The arrangement for supporting balls 24 and 25 of the second set may be identical with the described arrangement for the first set.

The necessary force to supply driving friction for the balls 22 and 23 is applied along the'thrust axis of the balls by means of the heavy spring 3| which is compressed between the hub of disc 2| and the inner race of the thrust bearing 32. The force is applied through disc 2|, balls 22 and 23, and disc 20, and is taken up by the thrust bearing 33 which supports one end of the shaft l8.

The arrangement for supplying driving friction for balls 25 and 25 includes the heavy spring 35 and is the same as that described in the case of balls 22 and 23.

The yoke 26 is slidabie on the rod 36, which extends lengthwise of the casing IE! just below the shafts H, I 8 and I5 and is fixed to the ends of the casing. Above the shafts l1, IB and I5 and extending parallel to the rod 35 there is a shaft 31 which has bearings in the ends of the casing. A spring 38 is provided to take up end-wise play in the bearings. The right hand end of shaft 31 projects through the end wall of the casing where it is provided with a knob 39, having a In order to indicate the position oftheyoke.

and the idler balls with reference to the discs, a calibrated bar 44 is provided. This bar is attached to the yoke 26 as shown and projects through the front wall of the casing along side of an index 43. The bar may be calibrated in terms of the pitch of the thread 42. The calibrated'bar can then be. read; as turns of the shaft 31 from the extreme or zero position and the dial. M) can be read as a fractional part of one turn of the shaft.

' The casing Ill should be partly filled with a good grade of lubricating oil, enough, oil being used so that; the rotation of the parts will be effective to lubricate the bearings.

The mechanism having been described, its op eration may now be explained briefly.

As: previously mentioned, power may be applied to the shaft. t2 in. any suitabl manner. Assumin: that a motor is used for this purpose, when the motor is started the shaft l2 drives the shaft tit-by means of worm l3 and worm gear I l. The

disc 2t, carried on; shaft 5, drives the ball 22, which drives the ball 23, and the latter ball in turn drives the disc 25 on shaft 18.. There is a gain in speed in the drive between the discs 2 l 26 due to the fact that ball 22 engages disc 21' at points lying on. a circle of relatively large diameter (nearly equal to the diameter of the disc) whereas the ball 23 engages disc at points lying on a circle which is considerably smailer in diameter. The rotating disc 20 drives hall ball. 25 drives ball 24, and the latter ball drives the disc l9'on shaft fl'. There is another and similar gain in speed in the drive betweeri discs 20 and t9.

The output shaft to, connected to shaft H, is new being rotated at its maximum speed, corresponding. to the zero setting of the indicator cam-4s and the dial. Mt. In this connection, it will. be noted that the indicator bar is so related to the position of the yoke that the bar reads zero when the balls 25 and 22 are at some distance from the edges of discs 2! and 2t, respectively; and that a somewhat higher speed of the output shaft could be attained by movement of the yoke still farther to the left. There is no danger of the balls slipping off the discs, for the yoke 26 will engag shaft l8 before this can happen, but it is not desirable to run the balls too close to the edges of the discs and accordingly the indicator bar is preferably arranged approximately as shown. That is, when it reads zero it indicates the limit of the speed range which is considered to be usable rather than the absolute limit.

In order to reduce the speed of the output shaft I6, the knob 39 is turned in a clockwise direction as seen in Fig. 1, thereby rotating shaft 31 and moving the yoke 26 and the idler balls to the right as seen in Fig. 2. The limit of movement in Vthis'direction is arrived at when the yoke engages the shaft l8, which it will do before. the balls=-24 and 23 can slip off the discs l9 and 2B. In practice, however, the yoke will not be moved quite so far, for reason pointed out above. With the yoke in its right hand position the output During this movement of the yoke the 26 is about 18 turns of the shaft 31, and an indicator bar reading of IS therefore corresponds to the lowest working speed of the output shaft.

desired intermediate speed for the. output shaft {6 can be obtained by properly adjusting the yoke 26 by means of the shaft 31 and knob 39 In this operation the indicator bar 44 counts the complet rotations of the shaft while the dial 4-8 acts as a Vernier and enables the operator to read an incompleted rotation of the shaft to a.- small fraction. Since there are 50 divisions on the dial it will be clear that if the yoke has a range of movement corresponding to 18' turns of the shaft 31, 900 difierent settings can be made without interpolation, each setting corresponding to a different. output speed.

In the manufacture of tapered conductors as disclosed in the application previously referred to herein, the conductor or wire to be tapered is made the anode in a system of electrolytic cells and successive sections of the wire are pulled through the cells at progressively lower speeds in order to subject them to anodic reduction for progressively longer periods and thus reduce the wire to a tapered formation. The production of tapered wire according to this method required a variable speed wire pulling mechanism, as will readily be appreciated.

The variable speed mechanism disclosed here in is well adapted for this purpose, as will be explained briefly.

The shaft 12 is driven by a synchronous motor, which is preferably driven from a source of current of constant frequency so that the input.

through the electrolytic cells. The gear ratio is so related to. the motor speed that the variable speed mechanism will cover the range of wire pulling speeds required.

The wire pulling speeds for the: different sections of the wire are accurately calculated and are expressed in seconds per foot. A curve or chart is therefore required by means of which the proper setting of the variable speed mechanism for any desired wire speed can be found.

. A curve is perhaps the most convenient to use and can be constructed by timing the variable speed mechanism at different settings thereof and then plotting the speeds thus obtained against the settings on suitable coordinate paper. The curve can be used for ascertaining the correct setting for any wire speed within the range of the mechanism. For making any particular taper th settings corresponding tothe different speeds are taken from the curve and are noted down. The wire is then pulled through the tapering apparatus, starting at the proper speed, and as each section leaves the apparatus the speed is changed by changing the setting of the variable speed mechanism; 1

As an example of the range; of wire pulling speeds that can be covered, it may be stated that with a variable speed mechanism constructed substantially as shown in the drawings, except that the pitch of the threads 42 on shaft; 31 was 20 threads to the inch, the wire speed correspending to Zero setting of the variable speed mechanism was 13 seconds per foot, while the wire speed corresponding to a setting of 19 was 457 seconds per foot. This is a sufficient range for the intended purpose, but could be increased if desired by increasing the diameter of the discs, which would permit a greater range of movement of the yok 26.

With loads such as are imposedby the wire tapering apparatus, and even with considerably greater loads, there is no appreciable slippage in the drive. Experience has shown that so long as the input speed remains constant a given setting will always produce the same output speed.

The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

I claim:

1. In a variable speed mechanism,'three discs, means supporting said discs for rotation with the second disc overlapping the first and third discs, two serially related balls coupling the first and second discs, two serially related balls coupling the second and third discs, and means for simultaneously moving both sets of balls to change the ratio of coupling, said last means including a support adapted to maintain said sets of balls a fixed distance apart on a diameter of the second disc.

2. In a variable speed mechanism, three discs, means supporting said discs for rotation with the second disc overlapping the first and third discs, two serially related balls coupling the first and second discs, two serially related balls coupling the second and third discs, resilient means tending to move said first and third discs toward said second disc to supply driving friction between said discs and balls, and means for simultaneously moving both sets of balls along radii of said discs, said last means including a support adapted to maintain said sets of balls a fixed distance apart on a diameter of the second disc.

3. In a variable speed mechanism, three discs, means supporting said discs for rotation with the second disc overlapping the first and third discs, two serially related balls coupling the first and second discs, two serially related balls coupling the second and third discs, means including a yoke for rotatably supporting said balls, and. means including a rotatable shaft threaded in said yoke for moving the same to change the position of said balls relative to the rotational axes of said discs.

4. In a variable speed mechanism, a rotatable disc, a second rotatable disc disposed in overlapping relation to said first disc, two serially related balls for coupling said discs together, and means including ball bearings for supporting said balls, each ball bearing comprising a plurality of balls engaging one of said coupling balls.

5. In a variable speed mechanism, two discs, means supporting said discs for rotation in overlapping relation on parallel axes, two serially related balls for coupling said discs, means for maintaining said balls in alignment along a line parallel to said axes, said last means comprising a movable support and ball bearings for said balls movably mounted on said support, and mounting means for each said ball bearing limiting the movement thereof to a direction which is parallel to the line on which said coupling balls are aligned.

6. In a variable speed mechanism, two discs, means supporting said discs for rotation in overlapping relation on parallel axes, two balls operatively disposed on a line normal to said discs to transmit power from on disc to the other, and means including ball bearings for supporting said balls for rotation on axes perpendicular to said line, said bearings including ball races supported for movement in a direction parallel to said line.

7. In a variable speed mechanism, three shafts supported parallel to each other in the same plane, three discs carried on said shafts, respectively, in overlapping relation to each other, a set of balls coupling the first and second discs, a second set of balls coupling the second and third discs, a fixed rod or bar extending perpendicularly past said shafts in spaced relation thereto, a lead screw extending parallel to said bar on the opposite side of said three shafts, a yoke supported on said bar and lead screw and slidable' on said bar responsive to rotation of said lead screw, and supporting means for said coupling balls carried by said yoke.

8. In a variable speed mechanism, three discs, means supporting said discs for rotation with the second disc overlapping the first and third discs, a set of serially related balls coupling the first and second discs, a set of serially related balls coupling the second and third discs, resilient means for maintaining said discs in frictional driving engagement with said balls, common support for both sets of balls, means for moving said support to move both sets of balls simultaneously along radii of said discs, and individual supporting means for each set of balls carried on said common support, said individual supporting means being movable on said common support in a direction perpendicular to said discs.

9. In a variable speed mechanism, a rotatable disc, a second rotatable disc disposed in overlapping relation to said first disc, two serially related balls for coupling said discs together, and two oppositely disposed ball bearings for supporting each of said coupling balls, each ball bearing comprising a circular ball race and a plurality of balls confined thereby which engage the associated coupling ball.

GORDON F. LAING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,325,323 Johnson et a1 July 27, 1943 2,357,035 Treese et al Aug. 29, 1944 2,209,254 Ahnger July 23, 1940 1,066,853 Sipp July 8, 1913 1,081,636 Sundh Dec. 16, 1913 1,803,834 Bates May 5, 1931 2,132,801 Perruca Oct. 11, 1938 692,391 Wagner Feb. 4, 1902 684,191 Chatham Oct. 8, 1901 FOREIGN PATENTS Number Country Date 87,088 Austria Jan. 25, 1922 19,771 France Apr, 2'7, 1915 816,982 Franc May 10, 1937 

